8,643 research outputs found

    A Memristor Model with Piecewise Window Function

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    In this paper, we present a memristor model with piecewise window function, which is continuously differentiable and consists of three nonlinear pieces. By introducing two parameters, the shape of this window function can be flexibly adjusted to model different types of memristors. Using this model, one can easily obtain an expression of memristance depending on charge, from which the numerical value of memristance can be readily calculated for any given charge, and eliminate the error occurring in the simulation of some existing window function models

    Modeling the Flux-Charge Relation of Memristor with Neural Network of Smooth Hinge Functions

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    The memristor was proposed to characterize the flux-charge relation. We propose the generalized flux-charge relation model of memristor with neural network of smooth hinge functions. There is effective identification algorithm for the neural network of smooth hinge functions. The representation capability of this model is theoretically guaranteed. Any functional flux-charge relation of a memristor can be approximated by the model. We also give application examples to show that the given model can approximate the flux-charge relation of existing piecewise linear memristor model, window function memristor model, and a physical memristor device

    Macroscopical Entangled Coherent State Generator in V configuration atom system

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    In this paper, we propose a scheme to produce pure and macroscopical entangled coherent state. When a three-level ''V'' configuration atom interacts with a doubly reasonant cavity, under the strong classical driven condition, entangled coherent state can be generated from vacuum fields. An analytical solution for this system under the presence of cavity losses is also given

    Modeling the AgInSbTe Memristor

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    The AgInSbTe memristor shows gradual resistance tuning characteristics, which makes it a potential candidate to emulate biological plastic synapses. The working mechanism of the device is complex, and both intrinsic charge-trapping mechanism and extrinsic electrochemical metallization effect are confirmed in the AgInSbTe memristor. Mathematical model of the AgInSbTe memristor has not been given before. We propose the flux-voltage controlled memristor model. With piecewise linear approximation technique, we deliver the flux-voltage controlled memristor model of the AgInSbTe memristor based on the experiment data. Our model fits the data well. The flux-voltage controlled memristor model and the piecewise linear approximation method are also suitable for modeling other kinds of memristor devices based on experiment data

    The challenge of emergence of virtual property to the traditional legal theory and the corresponding solutions

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    The emergence and popularity of virtual property has challenged traditional legal theory, especially property and intellectual property theory. Due to the predisposition for a desire of ownership, and the desire for security and certainty in investment, virtual property users should acquire new specific legal protection for their virtual property. This thesis argues that it is needed to establish an independent virtual property theory which could clarify the legal status of virtual property, the types of virtual property right and the allocation of ownership of virtual property in the virtual world. The majority of the current virtual property theories tend to confuse different types of code and content in virtual worlds, equating the underlying software (the building blocks of virtual worlds) and the user generated content (virtual assets). In this sense, this thesis proposes to construct a notion of virtual property through layer theory. The layer theory divides virtual property into three layers, namely infrastructure layer (1), abstraction layer (2) and content layer (3), based on distinguishing between codes which constitute a platform of the virtual world and codes which consist of the user generated content. The infrastructure layer (1) contains the internet service provides’ ISPs’ codes which constitute the platform of the virtual world. This level of virtual property could be considered as the fundamental basis of the operation of the virtual world. At the abstraction layer (2) sits the unique computer code which comprise of the unique items which designed by ISPs but have not transmitted to users in the virtual world. The content layer (3) are the virtual items which are closely relevant to specific individual due to their personal investment and arrangements. Virtual items that sit at the infrastructure layer (1) and abstraction layer (2) should be categorised as ISPs’ virtual property and should be protected as computer software or artistic works created by writing program under current copyright framework. The programmers’ employed by the ISPs are the author of both categorises of virtual property and the ISPs are the first owner of both types of virtual property. However once virtual property combines users’ skill, labour, personal information and other types of investment and arrangement, the added part then should be categorised as users’ virtual property and the ownership should be granted to ordinary users. Theoretically, this thesis defines virtual property as a piece of property which relies on the internet environment provided by ISPs and reflects both the legal relationship between users and ISPs and the relationship between users and others. This thesis also divides virtual property into three categories, the virtual property users get from ISPs directly without further reproduction and creation, the virtual property that contains users’ private information, and the virtual property enrich users’ originality and reproduction which even have not reach the requirement of copyright. Compared with the traditional property right model, taking the complex relationships reflected by virtual property, this thesis argues that virtual property rights granted to users should be a twofold virtual property right. The twofold virtual property rights system adopts what I term ‘restrained-exclusive property rights’ or ‘fundamental property rights’ to describe the ‘rights’ users can claim to regulate the relationship and conflict between them and ISPs, meanwhile ‘relative-exclusive property rights’ or ‘external property rights’ are used to describe owners’ property interests to prevent the infringement from other users. The twofold virtual property rights system will help courts to recognise the exclusive aspect of users’ virtual property right, clarify the property interest over users’ private information, and identify the originality in users’ virtual property. From the legislative perspective, this thesis suggests that virtual property should be explicitly stipulated in the current copyright framework in the UK due to the characteristic of the virtual property. As the ‘Copyright, Designs and Patents Act 1988’ (CDPA) states in s.1 that copyright is a property right. On the other hand, based on the virtual property theory proposed by this thesis, virtual property that sit at the infrastructure layer (1) and abstraction layer (2) should be protected as computer software or artistic works. Therefore, this thesis suggests that users’ virtual property should be regulated by an independent statute entitled ‘The Virtual Property Statute’ which will complement the current CDPA 1988

    Wireless pressure sensor system for fish quality monitoring

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    Food quality monitoring is increasingly important. This paper aims to propose the developed wireless pressure sensor system (WPSS) for fish quality monitoring. WPSS consists of a sensor acquisition module, power supply module, and Bluetooth module. The sensor acquisition module includes a temperature sensor, pressure sensor, and microcontroller unit (MCU). When Bluetooth receives the data collection command from the smartphone, the data of storage temperature and pressure in the food package can be collected by the sensor and transmitted wirelessly to the smartphone through Bluetooth. All data obtained by the system is monitored, stored, processed, and eventually displayed in a smartphone app in real-time to improve temperature, air pressure, and freshness transparency within the food package, ultimately ensuring food quality and safety. The proposed WPSS has potential application in many kinds of food monitoring. It can realize simple and intuitive food quality indications

    The effects of dog management on Echinococcus spp. prevalence in villages on the eastern Tibetan Plateau, China

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    Background The pastoral area of the eastern Tibetan plateau is a very important human echinococcosis endemic region. Domestic dogs are the main definitive host for the transmission of Echinococcus granulosus sensu lato (s.1.) and E. multilocularis to humans. To control the infection risks, a national-level canine echinococcosis prevention and control program has been implemented since 2015 in Shiqu County, Sichuan, China, The objective of this investigation was to evaluate its effect on Echinococcus spp. prevalence in dogs. Methods We surveyed 69 households with 84 owned dogs, for dog keeping information in the villages of Rizha and Eduoma. A total of 105 dog fecal samples, consisting of 75 from owned dogs and 30 unknown dog fecal samples were collected between 2015 and 2017 to determine Echinococcus spp. prevalence using copro-PCR. Eight variables based on household surveys were included into a logistic regression model for significantly relevant factors to canine echinococcosis prevalence in dogs. Results The overall Echinococcus spp. copro-DNA prevalence decreased significantly in dogs from 51.2% (2015) to 20.0% (2017) in Rizha, and insignificantly from 11.5% (2016) to 4.3% (2017) in Eduoma. Echinococcus multilocularis was the most prevalent species continually detected during the entire research period, while E. granulosus was rare and not detected in 2017. Echinococcus shiquicus prevalence was as high as E. multilocularis , although only detected in 2015 in Rizha. Unleashed dog feces were mainly collected in Rizha Village in 2015. Although 93.2% of owned dogs were leashed, and the monthly praziquantel dosing rate reached 97%, E. multilocularis infection could still be detected in 11.1% of owned dogs in 2017. Monthly deworming, leashing dogs 24h per day, and the avoidance of dogs feeding on livestock viscera are significant measures to prevent canine echinococcosis infection in owned dogs. Conclusion Carrying out a canine echinococcosis prevention and control program can significantly decrease the Echinococcus prevalence. The potential contact between leashed dogs and wild small mammals is still a risk to re-infect owned dogs. This study shows that the long term application of regular dog dosing in the vast remote echinococcosis endemic areas of west China is still challenging

    In an Attempt to Introduce Long-range Interactions into Small-world Networks

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    Distinguishing the long-range bonds with the regular ones, the critical temperature of the spin-lattice Guassian model built on two typical Small-world Networks (SWNs) is studied. The results show much difference from the classical case, and thus may induce some more accurate discussion on the critical properties of the spin-lattice systems combined with the SWNs.Comment: 4 pages, 3 figures, 18 referenc

    Evaluating the demand for aquaculture insurance: An investigation of fish farmers' willingness to pay in central coastal areas in China

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    Despite the remarkable development in its fishery sector, the penetration rate of fishery insurance in China is considerably low. This paper examines the key factors that contribute to the poor performance of fishery insurance, in particular aquaculture insurance, in China. The double-bounded dichotomous choice contingent valuation method (DB DCCVM) is used to investigate fish farmers’ willingness to pay (WTP) for an insurance program, based on a survey of 1280 fish farmers in three coastal cities in China. The results indicate that fish farmers’ decisions on adoption of an insurance scheme depend on various factors, among which magnitude of loss, fish farmers’ awareness toward insurance and their education all have a positive impact. However, income and farming years are more likely to have a negative effect. In addition, the mean WTP for aquaculture insurance is estimated to be CNY 579 (US$ 90.05) 2 per household, which is equivalent to 1.5% of fish farmers' mean annual income. These results provide several policy implications for not only the Chinese government but also researchers as well as insurance companies

    Spatiotemporal Changes in Extreme Precipitation in China’s Pearl River Basin during 1951–2015

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    Precipitation is a key component of the hydrological cycle and one of the important indicators of climate change. Due to climate change, extreme precipitation events have globally and regionally increased in frequency and intensity, leading to a higher probability of natural disasters. This study, using the long-term APHRODITE dataset, employed six precipitation indices to analyze the spatiotemporal changes in extreme precipitation in the Pearl River Basin during 1951-2015. The Mann-Kendall (M-K) test was used to verify the significance of the observed trends. The results indicate that: (1) the interannual PRCPTOT showed a trend with an average positive increase of 0.019 mm/yr, which was followed by an increase in SDII, R95P, and RX1day, and a decrease in R95D and CWD; seasonal PRCPTOT also displayed an increase in summer and winter and a decrease in spring and autumn, corresponding to increases in R95P and SDII in all seasons. (2) The annual precipitation increases from the west to east of the basin, similar to the gradient distribution of SDII, R95P and RX1day, with the high R95D happening in the middle and lower reaches of the Xijiang River, but the CWD increased from the north to south of the basin. The seasonal spatial distributions of PRCPTOT, SDII, and R95P are relatively similar except in autumn, showing an increase from the west to east of the basin in spring and winter and a gradual increase from the north to south of the basin in summer, indicating that the Beijiang and Dongjiang tributary basins are more vulnerable to floods. (3) The MK test results exhibited that the Yunnan-Guizhou Plateau region in the upper reaches of the Xijiang River Basin became drier, and there was an increase in extreme precipitation in the Beijiang and Dongjiang river basins. The study results facilitate valuable flood mitigation, natural hazard control and water resources management in the Pearl River Basin
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